The Verbal Interaction Project has developed and is studying, in a "before-after" experimental design, the Mother-Child Home Program for its short-term and long-range affective/cognitive effectiveness and its feasibility as a nationally applicable program for the prevention of educational disadvantage. The Program is a home-based, mother and family involving, cognitive/affective intervention program for two to four year olds in low-income families. The intervention is non- didactic in its approach to both mothers and children, with paid and volunteer adult women Toy Demonstrators trained to stimulate verbal interaction in mother-child dyads through play in Home Sessions focused around Verbal Interaction Stimulus Materials (selected toys and books). Short-term cognitive gains immediately after the two year program are consistently high and there is evidence of their total retention into kindergarten, accompanied by the child's above-average coping skills and positive quality in the mother's parenting skills. Major objectives of the investigation are: increase of N to about 1000 in yearly Program replications and variations in and out of laboratory; study of short-term and long-range cognitive/affective/academic effectiveness; program of refinement; experimental post-program reinforcement of gains; instrument development (measurement of affective variables); study of relationships among affective, cognitive, and other variables; re-analysis of demographic and other data to identify antecedents of "high rise" characteristics of one Untreated Group; study of perceptual-conceptual cognitive skills; concentration on dissemination, replication, and demonstration of Model Program 1976-1978.